Surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface. Surfactants are a primary component of most detergents. When dissolved in water, surfactants give a product the ability to remove dirt from surfaces. Each surfactant molecule has a hydrophilic head that is attracted to water molecules and a hydrophobic tail that repels water and simultaneously attaches itself to oil and grease in dirt. These opposing forces loosen the dirt and suspend it in the water.
Surfactants do the basic work of detergents and cleaning compositions by breaking up stains and keeping the dirt in the water solution to prevent re-deposition of the dirt onto the surface from which it has just been removed. Surfactants disperse dirt that normally does not dissolve in water.
Nonylphenol ethoxylates (NPEs) are predominantly used as industrial and domestic detergents as a surfactant. However, while effective, NPEs are disfavored due to environmental concerns. For example, NPEs are formed through the combination of ethylene oxide with nonylphenol (NP). Both NP and NPEs exhibit estrogen-like properties and may contaminate water, vegetation and marine life. NPE is also not readily biodegradable and remains in the environment or food chain for indefinite time periods.
Continued pressure to remove NPE and other phosphates from detergents has required an increase in caustics to preserve the effectiveness of the detergent. These caustics are strong alkalis, Lye (Sodium Hydroxide), Potassium Hypochlorite, or acids which are harmful if swallowed, particularly by small children. Some symptoms include severe pain, vomiting blood, heart collapse, breathing difficulty and burns or holes in the skin and underlying tissue. While the low phosphorous detergents are better for the environment, these detergents can be up to 100 times more caustic. Caustics also damage clothes through repeated use and can dull the fabric's color.
As can be seen there is a continuing need to develop effective, environmentally friendly, and safe surfactants and surfactant systems that can be used to improve cleaning ability in cleaners of all kinds. This is particularly so in light of several new cleaning challenges that have emerged.
Consumers have drastically increased use of sunscreens in light of recommendations by medical organizations such as the American Cancer Society. Sunscreen can prevent the squamous cell carcinoma and the basal cell carcinoma which may be caused by ultraviolet radiation from the sun. Many of these sunscreens contain components such as triglycerides, avobenzones and oxybenzones. These chemicals, while not visible prior to wash, typically appear on fabrics as yellow patches after washing with detergent-builder combinations at high pH. Current methods to treat these types of stains have included bleach, and other traditional pretreatments, to no avail.
As can be seen, there is a need in the industry for improvement of cleaning compositions, such as hard surface and laundry detergents and particularly the surfactants used therein so that difficult soils can be removed in a safe environmentally friendly and effective manner.